PREFACE 



All who have brought together and arranged large masses 

 of information " have had much trouble in sifting the 

 wheat from the chaff, often entailing infinite labour to 

 reach the truth about rare occurrences, etc. 



All assertions, however positive, of exceptionally rare 

 species which are unsupported by evidence cannot be 

 scientifically accepted by naturalists. The latter cannot 

 (ought not to be expected to) do violence to their own ex- 

 periences and knowledge of geographical distribution at 

 home and abroad ; or unquestioningly accept unproved 

 statements or utterly unsupported records of the breeding 

 in this country, for instance, of such species as the Fire- 

 crested Regulus, the Jack Snipe, Fieldfare, Redwing, 

 Purple Sandpiper, etc. 



Yet some people seem to consider it is enough for all 

 purposes to say, saw it," and "Therefore what I saw 

 must be what I saw it to be " ; but they have yet to satisfy 

 others who are students of distribution that they did not 

 see some quite different thing, or some other thing that 

 they had never seen before. Even ornithologists, for 

 instance, of the longest and widest experience are often 

 misled into similar side-ways ; but their experience tells 

 them not to be in haste to record without at least a saving 

 clause, such as, '* This is given not as a real record, but 

 only for what it is worth." 



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